package cn.ckx.coding.common.utils.http;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import javax.servlet.http.HttpServletRequest;

/**
 * IP地址工具
 * @author kunxin.cai
 */
@Slf4j
public class IpUtils {
    
    private static final String IP_UNKNOWN = "unknown";
    
    private static final int IP_DEFAULT_LENGTH = 15;
    
    private static final String IP_SEPARATOR = ",";
    
    /**
     * 获取IP地址
     * 使用Nginx等反向代理软件，则不能通过request.getRemoteAddr()获取IP地址
     * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
     * @return ip
     */
	public static String getIpAddress(HttpServletRequest request) {
    	String ip = null;
        try {
            ip = request.getHeader("x-forwarded-for");
            if (StringUtils.isEmpty(ip) || IP_UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
            }
            if (StringUtils.isEmpty(ip) || ip.length() == 0 || IP_UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
            }
            if (StringUtils.isEmpty(ip) || IP_UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
            }
            if (StringUtils.isEmpty(ip) || IP_UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
            }
            if (StringUtils.isEmpty(ip) || IP_UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
            }
        } catch (Exception e) {
        	log.error("无法读取ip地址，异常 : ", e);
        }
        
        //使用代理，则获取第一个IP地址
        if(StringUtils.isNotEmpty(ip) && ip.length() > IP_DEFAULT_LENGTH) {
			if(ip.indexOf(IP_SEPARATOR) > 0) {
				ip = ip.substring(0, ip.indexOf(IP_SEPARATOR));
			}
		}
        return ip;
    }
	
}
